1. Field of the Invention
The present invention relates to a polymer, and particularly to a polymer that could be applied to certain semiconductor manufacturing processes.
2. Related Prior Art
Integral circuit layering is crucial in semiconductor industries such that the number of integral layers on an integral circuit must be maximized. Therefore, narrower wire widths for lithography are required. To achieve better resolution, light sources with shorter wavelengths or exposure systems with larger numerical apertures are applied.
Recently, a tetrapolymer iBMA-MMA-tBMA-MMA (poly isobornyl methacrylate-methyl methacrylate-t-butyl methacrylate-methacrylic acid) is reported to be a possible resin system for ArF resist: 
For such polymers, there are still some disadvantages, for example, low etch resistance and bad adhesion due to the four monomer composition. Therefore, a new resin for the compositions of resists is eager to be developed.
U.S. Pat. No. 6,271,412 and 6,280,898 and Japanese Patent Publication No. 2001-242627 have disclosed-different polymers, which can form photoresist compositions and then be applied to semiconductor component manufacturing.
An object of the present invention is to provide a polymer having good thermal property as well as good hydrophilicity, adhesion and dry etch resistance. Furthermore, the polymer is characterized by penetrability of a 193 nm light source.
Accordingly, the polymer is comprised of formula (II) units, 
wherein R1 is H, haloalkyl group or C1-C4 alkyl group; R2 is hydroxyl group, C1-C8 alkoxy group or C1-C8 thioalkyl group; G is (CH2)n, O or S, wherein n is 0, 1,2,3 or 4; Rc is a lactone group; and m is 1, 2 or 3.
The polymer of the present invention can further be combined with a photo-acid generator (PAG), an acid quencher, an additive, a solvent, etc. To form a chemical amplified photoresist composition which can be applied to general lithography Processes, and particularly to the 193 n light source processes, whereby excellent resolution, figures and photosensitivity can be achieved. Such processes are well known by those skilled in this art.
The polymer of the present invention composes formula (II) units, where formula (II) units are essentially formed through a reaction involving a formula (I) compound, 
wherein R1 is H, haloalkyl group or C1-C4 alkyl group; R2 is hydroxyl group, C1-C8 alkoxy group or C1-C8 thioalkyl group; G is (CH2)n, O or S, wherein n is 0, 1 2, 3 or 4; Rc is a lactone group; and m is 1, 2 or 3.
This reaction can be performed by polymerization of the above compound or copolymerizing the above compound with other vinyl monomers in the existence of catalysts.
One of the methods for preparing the compound of formula (I) is shown as the following scheme, 
wherein R1, R2 and G are defined as the above.
In Step 1, a proper diene compound such as butadiene, cyclopentadiene, furan and thiophene, reacts with maleic anhydride to perform the Diels-Alder reaction. Then, the acid anhydride adducts are reduced under the well-known conditions in the Step 2. Preferably reaction is carried out using sodium boron hydride in dried polar solvent such as dimethylformamide or tetrahydrofuran. In Step 3, peroxide is provided to oxidize the double-bond compound into an epoxide. In Step 4, the epoxide reacts with a proper nucleophilic reagent such as water, alcohol and thiol, to perform a ring opening addition reaction under an acidic environment and then obtaining a hydroxyl derivative can be obtained. In Step 5, the hydroxyl derivative reacts with (alkyl)acryloyl chloride or acryloyl chloride to perform esterification resulting in and finally the compound of the formula (I) is obtained. Detailed procedures for preparing the compound of the present invention are described in the preferred embodiments.
The compounds of the formula (I) can be polymerized or copolymerized with other vinyl monomers to produce various polymers with or without the assistance of catalysts. Particularly, when being applied to the 193 nm processes, the vinyl monomers preferably have no aryl group to enable the light to pass therethrough. Below are some examples of vinyl monomers, wherein R3 is H, haloalkyl group, or C1-C4 alkyl group. 
The polymer of the present invention comprises the unit of the formula (II), 
wherein R1 is H, haloalkyl group or C1-C4 alkyl group; R2 is hydroxyl group, C1-C8 alkoxy group or C1-C8 thioalkyl group; G is (CH2)n, O or S, wherein n is 0, 1, 2, 3 or 4; Rc is a lactone group; and m is 1, 2 or 3.
The structure unit of the polymer or copolymers polymerized or copolymerized from compound (I) can be the following formula (III), formula (IV) or formula (V), 
wherein R, Rxe2x80x2 and Rxe2x80x3 each independently is H, haloalkyl group or methyl group. In the structure unit of formula (III) and (IV) g+h+i=1, more preferably g/(g+h+i)=0.01-0.8, h/(g+h+i)=0.01-0.8, i/(g+h+i)=0.01-0.8; in the structure unit of formula (V) g+h+i+j=1, more preferably g/(g+h+i+j)=0.01-0.5, h/(g+h+i+j)=0.01-0.8, i/(g+h+i+j)=0.01-0.8, j/(g+h+i+j)=0.01-0.8.
The above polymers can be used individually, or by mixing with one or more thereof.
The polymer of the present invention is preferably soluble in organic solvents, and has a glass transfer temperature (Tg) ranging from 50 to 220xc2x0 C., molecular weight ranging from 1,000 to 500,000, and degradation temperature (Td) larger than 80xc2x0 C.
The method for polymerization is not restricted, and is preferably done by mixing the above monomers in the existence of catalysts. The catalysts can be those well known by one skilled in this art, and preferably 2,2xe2x80x2-azo-bis-isobutyronitrile (AIBN) or dimethyl-2,2xe2x80x2-azo-bis-isobutyrate radical initiator (V-601).
The chemical amplified photoresist compositions of the present invention can be used in the process of lithography. Especially, the chemical amplified photoresist compositions of the present invention can be used in the process of 193 nm (ArF excimer laser) lithography.